Dependence of mean photospheric and coronal magnetic flux density ⟨|B_r(r)|⟩ on n_max. Upper panel: rotational values of ⟨|B_r(r)|⟩ in the photosphere (r = R_s) with n_max = 1, 2, 5, 10, 20, 50, 90 and the observed values from synoptic maps of 1800*900 and 360*180 pixels, respectively. Lower panel: ⟨|B_r(r)|⟩ in the coronal source surface (r_ss = 2.5R_S) using the same values of n_max as in the upper panel.